The use of a child booster seat in a vehicle to safely restrain a child in a vehicle seat is commonly required by government regulations and laws. A typical 3-point seat belt system cannot conveniently be used to restrain a child seated directly on the seat base of a typical vehicle seat because the seat belt webbing will not lie properly across the chest and in particular not low across the pelvis of the child. If the seat belt webbing of a seat belt system designed for an adult extends too high across a child's abdomen during a crash serious internal injury could result or the child could slide forward under the lap portion of the seat belt. FIG. 1 is a side elevation view of a child 1 occupying a typical vehicle seat 3 and sitting in a typical booster seat 5. The child's booster seat rests on the top face 7 of the seat base 6 of the vehicle seat to provide an elevated seating surface for the child. The booster seat has upstanding side walls 8. A recess 9 is formed in the front edge 10 of each side wall for receiving part of the seat belt webbing 20 of a typical 3-point seat belt system associated with the vehicle seat. The recess 9 is increased in depth downwardly at a location 11 spaced from the front edge 10 of the side wall 8 so as to resist separation of the seat belt webbing 20 from the booster seat 5, and separation of the booster seat 5 from the seat base 6. Typically a seat belt buckle tongue 2 is locked into a seat belt buckle 4 at a location above the seat base 6 to that it is juxtaposed with the side wall 8 of the booster seat.
Typical vehicle seats are associated with typical seat belt systems that are designed for adult use with the seat belt buckle positioned higher that the top face of the seat base for the convenience of an adult locking the seat belt buckle tongue with the seat belt buckle at a location that can be as much as 100 mm above the top face of the seat base. As a result of this configuration a lap portion of the seat belt if not redirected by the lower body of an adult would extend in a sloped path laterally across the seat base from a height of as much as 100 mm above the top face of the seat base to the opposite lateral edge of the seat base. It is to be understood that the term “lower body” refers to the portion of the human body below the waist. The lower body of a child seated directly on the seat base may not sufficiently engage the lap portion of the seat belt to adequately restrain the child to the vehicle seat. Hence the height of the seating surface of a typical booster seat is 100 mm high so that the lap portion of the seat belt directed by the belt guiding features of the booster seat properly engage the lower body of a child seated on the booster seat.
EC regulations require correct child restraints to be used for children aged three to twelve years and under 135 cm in height. Child restraints for children aged three to twelve years must be approved to R44.04. While adults responsible for enforcing a child's use of a booster seat have good compliance when a private automobile is used to transport a child, the inconvenience of toting a booster seat from vehicle to vehicle when using public conveyances, including school busses, results in lower compliance rates in such circumstances with children being inadequately restrained and protected. It is believed that the EC regulations could be complied with without the use of a booster seat by a vehicle seat according to the present invention.